1. Technical Field
The present invention relates to a digital-to-analog converter circuit, and in particular, to a resistive divider type digital-to-analog converter operable in connection with two different high side supply voltages.
2. Description of Related Art
Digital-to-analog converters are well known circuits. These circuit are presented in a variety of circuit configurations. Some configurations utilize a resistive divider circuit in connection with the conversion for producing the analog output signal from a multi-bit digital input. When such resistive divider based digital-to-analog converter circuits are fabricated as integrated circuits, a problem arises in that the resistors and associated transistors for tapping tend to occupy a significant amount of area. As emphasis is placing on reducing the area of an integrated circuit, the area occupied by the digital-to-analog converter becomes a significant concern.
A need accordingly exists in the art to provide a resistive divider type digital-to-analog converter which occupies less space. This can be accomplished, for example, by emphasizing a reduction in the number of resistors and transistors without giving up on sensitivity, step size and range.
It is further recognized that integrated circuits may have operational modes a different voltages. More specifically, the high side operating voltages for some part of the integrated circuit may change dependent on operational mode or some other factor. If the digital-to-analog converter is present in this part of the circuit, and if the digital-to-analog converter is resistive divider based, then this change in high side operating voltage may adversely affect converter operation and skew resolution and accuracy. There is accordingly a need in the art to address this issue and allow a single digital-to-analog converter to be used in connection with two different voltage sets.